G4 won't shut down: keeps restarting

[markj]

G4 500DP, OS 9.2.2.

Had a power outage the other day while working in Photoshop. Upon regaining power, the computer keeps restarting everytime I try to shut it down. Zapped PRAM, DiskWarrior etc..., but nothing's helping.

This happened once before when it was hooked up to a battery backup system; the machine was not on, but we lost power for a brief time. Upon regaining power, the machine mysteriously started back up on it's own. No problem since then until this problem now.

Please; any help?

Mark

[kaye]

A good place to start is here http://docs.info.apple.com/article.html?artnum=58171 and don't assume that because your USB devices worked just fine before, that it could not be one of them now.

Let us know your troubleshooting results. Luck. k

[markj]

Man you guys are GOOOOOOD!

Following the link you gave, I unplugged a Dr. Bott gHub 4-port USB hub and the machine shut down just fine.

I've recently noticed that at times, I was getting things like the mouse and keyboard not working after starting up, and I had to unplug and re-plug them inorder to get them working properly. This was driving me crazy; checking extensions, control panels, etc... until I unplugged the USB hub and all was well. Things went back to normal and the hub wasn't causing any problems with my keyboard/mouse.

Any ideas why the hub is causing problems intermittently? There are no drivers for it to conflict with.

Thanks again for help. This thing was driving me crazy and I was out of ideas.

Mark

[TZ]

MacIntouch has a special report on why OS X 10.2.5 and USB caused a lot of problems. Not all USB devices, cards, or hubs (k/b and mouse included) are made the same or up to spec.

I've had my own share of Dr Bott questions recently, so I no longer shop there first. OS 9 is usually more forgiving than Jaguar/OS X, but no longer. RAM, FireWire, USB, all the bugs out there get found out.